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Orchidaceae FAMILY Least Concern

Cypripedium acaule

Cypripedium acaule

Edibility
0/5
Medicinal
4/5

Safety & Hazards

We have no specific reports for this species but, especially during the flowering season, the glandular hairs on the leaves and stems of some N. American members of this genus can cause a rash, similar to poison ivy rash[1, 2]. The irritation is usually minor, or only lasts for a few minutes[3]. We have no specific information for this species, but it has been stated that the roots of at least one member of the genus may cause psychedelic reactions, and large doses may result in giddiness, restlessness, headache, mental excitement and visual hallucinations[4].

Cultivation Details

HabitPerennial
Growth—

Cypripedium acaule is a very cold-tolerant plant, when fully dormant it can withstand temperatures down to about -25°c[5]. Requires a position in semi-shade on a damp acid soil that is rich in humus[5]. Found in the wils on sandy soils that are rich in humus, strongly acidic and well aerated[1]. Plants grow well in a woodland garden or shady border[6]. Orchids are, in general, shallow-rooting plants of well-drained low-fertility soils. Their symbiotic relationship with a fungus in the soil allows them to obtain sufficient nutrients and be able to compete successfully with other plants. They are very sensitive to the addition of fertilizers or fungicides since these can harm the symbiotic fungus and thus kill the orchid[6]. Resents root disturbance[5]. A very ornamental plant[7], it is quite difficult in cultivation and plants will often flower well in their first year then disappear[6]. This is possibly because the plants are sold bare-rooted and do not have the necessary fungal symbiant they need in order to thrive[6]. Only buy pot-grown plants in order to try and ensure that the symbiant is present[PFAF]. The flowers of Cypripedium species belong to the group of 'trap' flowers. An insect as it crawls in, can only escape from the slipper-like labellum through a tunnel near the base of the labellum from where it is directed first to the nearby stigma where possible pollinia from another flower on its back are stripped off and while escaping, sticky pollen from the nearby anthers adhere to its back for the pollination of another flower[8]. The plants are subject to damage by slugs[5].

Propagation

Seed - surface sow, preferably as soon as it is ripe, in the greenhouse and do not allow the compost to dry out. The seed of this species is extremely simple, it has a minute embryo surrounded by a single layer of protective cells. It contains very little food reserves and depends upon a symbiotic relationship with a species of soil-dwelling fungus. The fungal hyphae invade the seed and enter the cells of the embryo. The orchid soon begins to digest the fungal tissue and this acts as a food supply for the plant until it is able to obtain nutrients from decaying material in the soil[5]. It is best to use some of the soil that is growing around established plants in order to introduce the fungus, or to sow the seed around a plant of the same species and allow the seedlings to grow on until they are large enough to move. Division with care in early spring, the plants resent disturbance[5]. Remove part of the original rootball, making sure to keep some of the soil around it intact[5]. Division is best carried out towards the end of the growing season, since food reserves are fairly evenly distributed through the rhizome[6]. Small divisions of a lead and two buds, or divisions from the back (older) part of the rhizome without any developed buds, establish quickly using this method[6]. Replant immediately in situ[6]. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Cypripedium+acaule>

Pollinators

Bees, Insects

References

  1. [1]IUCN Red List of Threatened Species — http://www.iucnredlist.org/ ↩︎A list of plants under threat and facing possible extinction, usually with brief details of the threats and information on habitat.
  2. [2]BoDD (Botanical Dermatology Database) — http://bodd.cf.ac.uk/ ↩︎Brief notes on a very wide range of plants that have reports of causing harm to the skin.
  3. [3]Poisonous Plants of North Carolina — http://www.ces.ncsu.edu/depts/hort/consumer/poison/poison.htm ↩︎An excellent concise but comprehensive guide to toxic plants that grow in N. Carolina. It lists even those plants that are of very low toxicity, including several well-known food plants such as carrots and potatoes.
  4. [4]Herbal Medicines. Third Edition — Barnes J., Anderson L.A. & Phillipson J.D. · Pharmaceutical Press; London · 2007 · ISBN 978 0 85369 623 0 ↩︎Providing mongraphs on 152 medicinal plants with lots of references to allow further research. A very good book, it can be downloaded from the Internet
  5. [5]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
  6. [6]Hardy Orchids. Orchids for the Garden and Frost-free Greenhouse. — Cribb. P. & Bailes. C. · Christopher Helm. London. · 1989 · ISBN 0 7470 0416 1 ↩︎An excellent book looking at the orchids that can be grown outdoors in temperate climates and giving lots of information on how to grow them. Very lttle information on their uses.
  7. [7]The History and Folklore of North American Wild Flowers. — Coffey. T. · Facts on File. · 1993 · ISBN 0-8160-2624-6 ↩︎A nice read, lots of information on plant uses.
  8. [8]Flora of Pakistan — http://www.efloras.org ↩︎As of 2006, there is not much information on habitats available, but it is being developed and promises to be an excellent resource.
  9. [9]Flora of N. America — http://flora.huh.harvard.edu/fna/ ↩︎An on-line version of the flora with an excellent description of the plant including a brief mention of plant uses.
  10. [10]A Field Guide to Medicinal Plants. Eastern and Central N. America. — Foster. S. & Duke. J. A. · Houghton Mifflin Co. · 1990 · ISBN 0395467225 ↩︎A concise book dealing with almost 500 species. A line drawing of each plant is included plus colour photographs of about 100 species. Very good as a field guide, it only gives brief details about the plants medicinal properties.
  11. [11]Native American Ethnobotany — Moerman. D. · Timber Press. Oregon. · 1998 · ISBN 0-88192-453-9 ↩︎Very comprehensive but terse guide to the native uses of plants. Excellent bibliography, fully referenced to each plant, giving a pathway to further information. Not for the casual reader.
  12. [12]Earth Medicine, Earth Food. — Weiner. M. A. · Ballantine Books · 1980 · ISBN 0-449-90589-6 ↩︎A nice book to read though it is difficult to look up individual plants since the book is divided into separate sections dealing with the different medicinal uses plus a section on edible plants. Common names are used instead of botanical.
  13. [13]Medicinal Orchids of Asia — Eng Soon Teoh · Springer International Publishing Switzerland · 2016 · https://doi.org/10.1007/978-3-319-24274-3 · ISBN 978-3-319-24272-9 ↩︎
  14. [PFAF]Plants for a Future — pfaf.org ↩︎